Crop Protection Network
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Protecting crops, hopper to harvest. Extension expertise for the United States and Canada.
Scouting 101 Wireworms (true [Elateridae] and false [Tenebrionidae]) in cotton Description True wireworms (larvae of click beetles, Elateridae: e.g., Conoderus, Aeolus, Limonius spp.) and false wireworms (larvae of darkling beetles, Tenebrionidae: e.g., Eleodes, Blapstinus spp.) are hard-bodied, segmented, yellow-to-dark-brown larvae (~1 inch long at maturity) with three pairs of legs near the head that feed on cotton seedling roots, hypocotyls, cotyledons, and growing points, causing stand reduction, stunting, wilting, yellowing, increased disease susceptibility, severed plants, and “Christmas tree” terminal growth—most severe in reduced/no-till fields, following grain/cover crops, or in sandy/dry soils of the Texas High Plains and Rolling Plains. Preferred scouting method Place grain bait traps (whole wheat or 1:1 wheat:corn in mesh sock, soaked 24 hours, buried 6 inches deep) in fields a few weeks before planting (when soil temperature ≥50°F); retrieve after 10–14 days to count larvae; supplement with visual excavation of seedlings (planting to 4–5 leaf stage) for larvae/damage and observation of darkling beetle (Blapstinus) adults at plant bases or under debris in dry areas. Economic threshold None established; use preventive management based on field history (prior infestations, reduced tillage, preceding grain/cover crops, or bait trap detections). Economic injury level: Not defined separately (preventive tactics avoid stand-loss injury); no temperature adjustments noted (scout at soil temps ≥50°F). Recommended insecticide(s) with labeled rate(s) per acre Seed treatments (neonicotinoids; standard commercial cotton packages) imidacloprid (e.g., Acceleron Standard/Elite, Prime, CottolyST Enhanced/Premier, PhytoGen TRiO, Avicta Elite) or thiamethoxam + imidacloprid combinations at labeled rates (typically 0.3–0.5 mg ai/seed; consult specific brand for exact mg ai/seed) In-furrow at-plant (high-risk fields) aldicarb (AgLogic 15GG) 3.5–5 lb/acre imidacloprid or phorate at labeled rates Foliar (adult darkling beetles only) pyrethroids or other labeled adulticides when large numbers + clipping threaten stand (use per current Texas cotton labels) agrilife.org/texasrowcrops/…
